Tamil nationalists attacked a bus late Tuesday carrying ethnic Sinhalese Sri Lankans who were visiting India, the latest sign of ethnic tensions that could imperil New Delhi’s relationship with Colombo.

About two hundred Sri Lankan tourists were on their way to an airport in India’s southern Tamil Nadu state late Tuesday when a mob led by the regional Marumalarchi Dravida Munnetra Kazhagam party hurled stones at their buses and smashed several windows, say police authorities. There were no injuries and police escorted the tourists to the airport, from where they returned to Sri Lanka.

The incident comes amid sharp rhetoric in Tamil Nadu against the Sinhalese majority in Sri Lanka.

Tamil Nadu’s population is mainly ethnic Tamil, a largely Hindu religious group. The mainly Buddhist Sinhalese dominate Sri Lanka, a country that is separated from Tamil Nadu by the narrow Palk Strait.

Sri Lanka’s Sinhalese-dominated army fought a brutal 26-year war against the country’s Tamil minority that killed tens of thousands, largely Tamil civilians, before its conclusion in 2009. During that conflict, the Tamil Tiger insurgents often sheltered in Tamil Nadu.

Recent anti-Sinhalese developments in Tamil Nadu show the wounds of the war have not yet healed.

On Sunday, the state’s chief minister, Minister J. Jayalalithaa, who heads a large Tamil nationalist party, caused waves when she cancelled a local soccer tournament involving a visiting Sri Lankan team, claiming that such interactions “humiliated the people of Tamil Nadu.”

Last month, Ms. Jayalalithaa wrote Indian Prime Minister Manmohan Singh to demand the immediate end of Indian military training for Sri Lankan officers.

Mr. Singh’s administration rebuffed that call. But rising anti-Sri Lankan sentiment in Tamil Nadu has caused a headache for the government.

Back in March, New Delhi voted in favor of a U.S.-sponsored resolution at the United Nations that demanded Sri Lanka investigate human rights abuses carried out by its forces at the end of the civil war.

India’s government, which had previously resisted censuring Sri Lanka on its rights record, was forced to back the U.N. resolution due to pressure from a Tamil Nadu-based party that is part of the national governing coalition.

Still, India, which is a large aid donor to Sri Lanka and South Asia’s regional power, does not want to see its relations slide further with Colombo.

On Tuesday, India’s foreign ministry attempted to rein in potential damage from the attacks on the Sri Lankan tourists.

“The government of India, in close consultation with the State governments concerned, has taken and will continue to take all measures to ensure the safety, security and well-being of Sri Lankan dignitaries and visitors to India, including to Tamil Nadu,” foreign ministry spokesperson Syed Akbaruddin said in a statement.

Sri Lankan politicians have called on India to stop the violence against its citizens. The country’s foreign ministry advised Sri Lankans visiting the Indian state to return home “in the interest of their security” and requested others to defer any “visits to Tamil Nadu until further notice.”

“It is one thing for the chief minister to rant against India’s military relations with Sri Lanka. It is insane to tell ordinary Sri Lankans – whatever the ethnicity – that they are not welcome to Tamil Nadu,” Mr. Swamy noted in an IBN 7 opinion column Tuesday.

Indian commentators, too, have taken the chief minister to task for her stance.

A Tuesday editorial in The Hindu, a leading Indian newspaper, said she had “tarnished the reputation of India as an open and tolerant society,” adding that this could sour diplomatic ties between the neighboring countries

Some political analysts, though, argued in favor of limiting visits by Sri Lankans to Tamil Nadu.

“It’s just been three years since the civil war ended,” noted S. Chandrasekharan, the director of the South Asia Analysis Group, a New Delhi-based think-tank. “Wounds from the war are still fresh and that’s evident from recent cases of violence in the state,” he added.

“It’s better to limit interactions than fuel violent attacks and put at risk the lives of innocent Sri Lankans,” he opined.

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